Site Navigation

Site Mobile Navigation

Pesticides Linked to Endometriosis Risk

Why some women and not others get endometriosis — the growth of uterine tissue outside the uterus that can cause pain and infertility — is not known, but researchers have come up with one possible contributing factor: pesticide poisoning.

Scientists studied 248 women with surgically confirmed endometriosis and 538 healthy controls. They measured blood levels of two pesticides, mirex and beta HCH, which persist in some fish and dairy products even though their use in the United States has been banned for decades. The study appears online in Environmental Health Perspectives.

The researchers found that women with the highest exposure to mirex had a 50 percent increased risk for endometriosis, and those exposed to high levels of beta HCH a 30 to 70 percent increased risk.

The association persisted even after adjusting for age, serum lipids, education, race and ethnicity, smoking, alcohol intake and other factors.

Kristen Upson the lead author, who was a predoctoral fellow at the Fred Hutchinson Cancer Research Center when the work was done, said the reasons for the association are unclear. But, she said, the chemicals have been shown to interfere with normal estrogen action in animal and tissue studies, which might be a possible explanation for the illness in humans.

“Persistent environmental chemicals,” she added “even those used in the past, may affect the health of the current generation of reproductive-age women.”

A version of this article appears in print on 11/05/2013, on page D6 of the NewYork edition with the headline: Awareness: Pesticides and Endometriosis.